CVE-2026-65904
MEDIUM
NVD
CVSS Score
4.7
Severity
MEDIUM
Published
Jul 23, 2026
Vendor
unknown
Description
DOMPurify through 3.3.3 fails to sanitize DOM elements passed via IN_PLACE mode when the element originates from a different window/realm (e.g., an iframe's contentDocument). A cross-realm instanceof check in the private _isNode() function returns false for foreign-realm nodes, causing DOMPurify to stringify the element (yielding '[object HTMLDivElement]'), silently reset IN_PLACE to false, and return the unsanitized element unchanged with any XSS payloads intact. The vendor considers this an edge case outside DOMPurify's threat model and, at time of publication, no fix was planned.